Table of contents

We are delighted to come up with thirty two (32) contributed research papers in these proceedings, focusing on Materials Science and Applied Physics as an output of the 2013 International Conference in Applied Physics and Materials Science (ICAMS2013) held on October 22-24, 2013 at the Ateneo de Davao University, Davao City, Philippines. The conference was set to provide a high level of international forum and had brought together leading academic scientists, industry professionals, researchers and scholars from universities, industries and government agencies who have shared their experiences, research results and discussed the practical challenges encountered and the solutions adopted as well as the advances in the fields of Applied Physics and Materials Science. This conference has provided a wide opportunity to establish multidisciplinary collaborations with local and foreign experts.

ICAMS2013, held concurrently with 15th Samahang Pisika ng Visayas at Mindanao (SPVM) National Physics Conference and 2013 International Meeting for Complex Systems, was organized by the Samahang Pisika ng Visayas at Mindanao (Physics Society of Visayas and Mindanao) based in MSU-Iligan Institute of Technology, Iligan City, Philippines. The international flavor of converging budding researchers and experts on Materials Science and Applied Physics was the first to be organized in the 19 years of SPVM operation in the Philippines. We highlighted ICAMS2013 gathering by the motivating presence of Dr. Stuart Parkin, a British Physicist, as one of our conference's plenary speakers. Equal measures of gratitude were also due to all other plenary speakers, Dr. Elizabeth Taylor of Institute of Physics (IOP) in London, Dr. Surya Raghu of Advanced Fluidics in Maryland, USA and Prof. Hitoshi Miyata of Niigata University, Japan, Prof. Djulia Onggo of Institut Teknologi Bandung, Indonesia, and Dr. Hironori Katagiri of Nagaoka National College of Technology, Japan.

The warm hospitality of the host university, Ateneo de Davao University, Davao City, Philippines blended with the overwhelming enthusiasm of the conference speakers, participants, and the unwavering support of the conference sponsors and donors and the administration of the MSU-Iligan Institute of Technology, Iligan City, Philippines, all have brought realization to the production of these proceedings.

The photographs from the conference can be viewed in the PDF file.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

A The White Noise Path Integral Approach is used in evaluating the B-cell density or the number of B-cell per unit volume for a basic type of immune system response based on the modeling done by Perelson and Wiegel. From the scaling principles of Perelson [1], the B- cell density is obtained where antigens and antibodies mutates and activation function f(|S-S_A|) is defined describing the interaction between a specific antigen and a B-cell. If the activation function f(|S-S_A|) is held constant, the major form of the B-cell density evaluated using white noise analysis is similar to the form of the B-cell density obtained by Perelson and Wiegel using a differential approach.A piecewise linear functionis also used to describe the activation f(|S-S_A|). If f(|S-S_A|) is zero, the density decreases exponentially. If f(|S-S_A|) = S-S_A-S_B, the B- cell density increases exponentially until it reaches a certain maximum value. For f(|S-S_A|) = 2S_A-S_B-S, the behavior of B-cell density is oscillating and remains to be in small values.

Self-propelled droplets have been conceived as simple chemical toy models to mimic motile biological samples such as bacteria. The motion of these droplets is believe to be due to the surface tension gradient in the boundary of the droplet. We performed experiments to look at the effect of varying the medium viscosity to the speed of a circular boat that was soaked in Pentanol. We found that the boats undergo oscillatory type of motion inside a channel. Moreover we found the maximum speed of the boat is independent on the viscosity of the medium. On the other a time scale describing the width of the velocity profile of the boat was found to increase with increasing viscosity.

This study investigates on the sound pressure level (SPL) of insert-type earphones that are commonly used for music listening of the general populace. Measurements of SPL from earphones of different respondents were measured by plugging the earphone to a physical ear canal model. Durations of the earphone used for music listening were also gathered through short interviews. Results show that 21% of the respondents exceed the standard loudness/duration relation recommended by the World Health Organization (WHO).

The quality of epitaxial graphene on silicon (GOS) is negatively correlated with the residual stress of the 3C-SiC films grown on the Si substrates. This has been systematically demonstrated by use of a series of 3C-SiC films formed on Si(110) substrates with varied residual stress. The residual stress of the3C-SiC film and the grain size of graphene were estimated with Raman-scattering spectroscopy while the crystallinity of the3C-SiC filmwasevaluated by x-ray diffraction. The more it reduces the residual stress the better the GOS quality it becomes. In particular, use of the rotated epitaxial film of 3C-SiC formed on Si(110) substrate, which gives the lowest residual stress, is found to produce a graphene with one of the best quality ever obtained in GOS. The revealed GOS quality improvement opens new opportunities for the production of high-performance GOS-based devices.

This special project presents a 10-Bit 1Gs/s 1.2V/3.3V Digital-to-Analog Converter using1 Poly 9 Metal SAED 90-nm CMOS Technology intended for mixed-signal and power IC applications. To achieve maximum performance with minimum area, the DAC has been implemented in 6+4 Segmentation. The simulation results show a static performance of ±0.56 LSB INL and ±0.79 LSB DNL with a total layout chip area of 0.683 mm².The segmented architecture is implemented using two sub DAC's, which are the LSB and MSB section with certain number bits. The DAC is designed using 4-BitBinary Weighted DAC for the LSB section and 6-BitThermometer-coded DAC for the MSB section. The thermometer-coded architecture provides the most optimized results in terms of linearity through reducing the clock feed-through effect especially in hot switching between multiple transistors. The binary- weighted architecture gives better linearity output in higher frequencies with better saturation in current sources.

Starting with a set of basic assumptions and with the application of well-known Newtonian physics, a theoretical model has been established for the flight of the mahogany winged seed. Using a high-speed camera, we successfully confirmed that the mahogany winged seed attains a vertical and rotational terminal velocity. From our model the mahogany seed has a terminal speed of 1.45 m/s. The experimental value of the terminal velocity on the average is 1.47 m/s (only about 1% error). The experimental value of the angular velocity was found to be around 54.33 rad/s, about 14% error compared to the predicted terminal velocity of 47.5 rad/s. The high predictable nature of a mahogany's terminal velocity can facilitate the biologist's study of mahogany mass seed dispersal.

The validity of ERPs as indices of stable neurophysiological traits is partially dependent on their stability over time. Previous studies on ERP stability, however, have reported diverse stability estimates despite using the same component scoring methods. This present study explores a novel approach in investigating the longitudinal stability of average ERPs—that is, by treating the ERP waveform as a time series and then applying Euclidean Distance and Kolmogorov-Smirnov analyses to evaluate the similarity or dissimilarity between the ERP time series of different sessions or run pairs. Nonlinear dynamical analysis show that in the absence of a change in medical condition, the average ERPs of healthy human adults are highly longitudinally stable—as evaluated by both the Euclidean distance and the Kolmogorov-Smirnov test.

ZnO nanostructures grown on glass (SiO2) substrates have been successfully fabricated for ethanol gas sensor. These ZnOnanostructures were prepared by chemical bath deposition with various ammonium hydroxide concentrations. The response of ZnO- based ethanol gas sensor exhibited higher response at lower NH4OH concentration; this might be attributed to the uniform morphology of the ZnOnanostructures which facilitates easier interaction with the ethanol gas. On the other hand, at higher NH4OH concentration showed drastic decrease in sensor response. This might be due to the growth of broken nanorods. Scanning electron microscope (SEM) images confirmed the formation of uniform and vertically grown nanostructures with lower concentration of NH4OH. On the other hand, at higher NH4OH concentration, broken nanorodsand agglomerations were present as revealed in the SEM micrographs. Energy dispersive x-ray spectroscopy (EDS) measurements suggested that the grown nanostructures were most likely composed of ZnO. The calculated energy band gap from the UV-Vis spectra confirmed that the grown Zn Onanostructures.

This study aims to develop a prototype for an Automated Car Park Management System that will increase the quality of service of parking lots through the integration of a smart system that assists motorist in finding vacant parking lot. The research was based on implementing an operating system and a monitoring system for parking system without the use of manpower. This will include Parking Guidance and Information System concept which will efficiently assist motorists and ensures the safety of the vehicles and the valuables inside the vehicle. For monitoring, Optical Character Recognition was employed to monitor and put into list all the cars entering the parking area. All parking events in this system are visible via MATLAB GUI which contain time-in, time-out, time consumed information and also the lot number where the car parks. To put into reality, this system has a payment method, and it comes via a coin slot operation to control the exit gate. The Automated Car Park Management System was successfully built by utilizing microcontrollers specifically one PIC18f4550 and two PIC16F84s and one PIC16F628A.

Polyanilinefilms doped with varying HClconcentrations (0.2 M, 0.6 M and 1.0 M) were synthesized on glass substrates via oxidative polymerization of aniline. The films were treated with supercritical carbon dioxide (SC-CO₂) at 30 MPa and 40°C for 30 minutes. Their structural, optical and morphological properties were studied and compared to conventionally prepared polyanilinefilms using FTIR analysis, UVVisspectroscopy and scanning electron microscopy. It was observed that supercritical carbon dioxide (SC-CO₂) could interact with PANI films that consequently altered the bandgapsand changed the film thickness. SC-CO₂ treatment also increased the oxidation level of polyanilinefilms and modified the morphology of polyanilinefilm doped with 1M HCl.

Presented in this paper is an experimental comparison of the conventional and proposed design circuit of a radio frequency (RF) energy harvesting. RF to DC energy harvester simply consists of antenna and rectifier block for receiving electromagnetic radiation signal and to produce a DC voltage, respectively. In addition to this conventional circuit, the proposed design includes LC tank circuit as receiving block of a well-designed antenna radio frequency receiver. Proper choice of an antenna type, realizing of point contact Germanium diodes as rectifier and correct design values for the LC passive components, greatly improved the measurement of the maximum output power, giving approximately a 100% increase compared to the conventional method. Experimental results of the enhanced RF to DC converter measured a maximum output power of 1.80 mWat a distance of 77.84 meters from a TV signal tower operating at 165 MHz.Thus, the harvested signal was enough to supply a low power wireless device applications without battery maintenance.

This paper presents derivation of the probability distribution for the area enclosed by a polymer loop in a gel and under different external fields using white noise analysis. In this context, the polymer loop is represented by Brownian paths and its immersion in a gel constraints it to occupy a constant area[1]. The external fields considered are electric field, and crossed electric-magnetic fields.

We report on our experimental investigation of the dynamics of a passive tracer in a bath of active self-propelling granular particles. We found a caging like dynamics of the passive tracer such that for low active particle concentrations the passive tracer exhibits longer periods of inactivity. For increasing active particle concentration the occurrence of short period inactivity increases.

We study interbanddipole transitions across curvature-induced narrow gaps in quasi-metallic single-walled carbon nanotubes. The curvature effects not only open a gap in the nanotube energy spectrum but also allow optical transitions, which happen to be in the highly- desired terahertz frequency range. Applying a magnetic field along the nanotube axis allows one to tune the frequency peaks in the spectral density of absorption.

We are developing compact electron linear accelerators (hereafter linac) with high RF (Radio Frequency) frequency (9.3 GHz, wavelength 32.3 mm) of X-band and applying to medicine and non-destructive testing. Especially, potable 950 keV and 3.95 MeV linac X-ray sources have been developed for on-site transmission testing at several industrial plants and civil infrastructures including bridges. 6 MeV linac have been made for pinpoint X-ray dynamic tracking cancer therapy. The length of the accelerating tube is ∼600 mm. The electron beam size at the X-ray target is less than 1 mm and X-ray spot size at the cancer is less than 3 mm. Several hardware and software are under construction for dynamic tracking therapy for moving lung cancer. Moreover, as an ultimate compact linac, we are designing and manufacturing a laser dielectric linac of ∼1 MeV with Yr fiber laser (283 THz, wavelength 1.06 pm). Since the wavelength is 1.06 μm, the length of one accelerating strcture is tens pm and the electron beam size is in sub-micro meter. Since the sizes of cell and nuclear are about 10 and 1 μm, respectively, we plan to use this "On-chip" linac for radiation-induced DNA damage/repair analysis. We are thinking a system where DNA in a nucleus of cell is hit by ∼1 μm electron or X-ray beam and observe its repair by proteins and enzymes in live cells in-situ.

Growth of zinc oxide on plain and Pt-coated glass substrate via chemical bath deposition technique (CBD) were studied. Aqueous solutions of ammonium hydroxide (NH4OH) and zinc sulfate (ZnSO4) were used as the precursor substances in the synthesis. Ultraviolet-visible spectroscopy (UV-Vis) was performed to determine the energy band gap and X-ray diffraction (XRD) to examine crystallinity. Sensitivity measurements were carried out in order to examine its potential to be fabricated as hydrogen peroxide (H2O2) gas sensor. Experimental results in the sensitivity experiment show that in the presence of H2O2 gas, the resistance of ZnOincrease which can be used as the basis for H2O-2 detection. UV-Vis showed variation of energy band gap values but were all near the generally accepted value. XRD spectra further verify that ZnOwere indeed synthesized.

A full-custom design of an element selection algorithm, named as Split-set Data Weighted Averaging (SDWA) is implemented in 90nm CMOS Technology Synopsys Library. SDWA is applied in seven unit elements (3-bit) using a thermometer-coded input. Split-set DWA is an improved DWA algorithm which caters the requirement for randomization along with long-term equal element usage. Randomization and equal element-usage improve the spectral response of the unit elements due to higher Spurious-free dynamic range (SFDR) and without significantly degrading signal-to-noise ratio (SNR). Since a full-custom, the design is brought to transistor-level and the chip custom layout is also provided, having a total area of 0.3mm2, a power consumption of 0.566 mW, and simulated at 50MHz clock frequency. On this implementation, SDWA is successfully derived and improved by introducing a register at the output that suppresses the jitter introduced at the final stage due to switching loops and successive delays.

Measuring liquid level and solution concentration play an important role in commercial and technological applications. For years, polymer optical fibers (POFs) have been very attractive for industrial applications because of their unique characteristics. In this work, we created simple, low cost and efficient set-up for sensing liquid level and solution concentration using POFs. We have calculated the acceptance angle of the POF to be 30°from numerical aperture (NA) measurements (NA ≈ 0.500).Images of a single POF showed the presence of impurities within the fiber which can contribute to power loss of the transmitted light. Light leakage was also observed when the fiber was bent to a tight radius, i.e. beyond its minimum bend radius of 15 mm. The experimental results show that as liquid level increases, the output power decreases. Furthermore, when the liquid concentration was increased, its response showed a greater loss of optical power due to the light rays in the submerged region of the POF tend to be refracted out of the fiber instead of being totally internally reflected and transmitted when index of refraction of the surrounding liquid medium is increased.

The objective of this study is to validate the Inoue method so that it would be the preferential choice in determining glomerular filtration rate (GFR) in Philippine pediatrics. The study consisted of 36 patients ranging from ages 2 months to 19 years old. The subjects used were those who were previously subjected to in-vitro method. The scintigrams of the invitro method was obtained and processed for split percentage uptake and for parameters needed to obtain Inoue GFR. The result of this paper correlates the Inoue GFR and In-vitro method (r = 0.926). Thus, Inoue method is a viable, simple, and practical technique in determining GFR in pediatric patients.

Poly(3,4-ethylenedioxythiophene) (PEDOT)-κ-carregeenan polymer electrolyte blend was prepared and incorporated as the electrolyte system in dye-sensitized solar cells (DSSC). Polymer blends prepared with different κ-carrageenan concentrations and molecular weights were investigated. It was found that the conductivity of the polymer blend increases with higher κ-carrageenan concentration, and lowers with degraded κ-carregeenan. The polymer blend was incorporated in a DSSC and yielded a solar cell with efficiency (η) of 0.421%.

Spin crosoveriron(II) complexes have potential applications as smart materials since the complexes show reversible transition between diamagnetic low-spin(LS) state and a paramagnetic high spin(HS) state under the application of temperature change, pressure or light irradiation. The complexes generally prepared as a powder compound isolated from direct reaction between aqueous iron(II) solutions with ligand in ethanol or methanol solution. For application as electronic molecular devices, the complex was prepared as a thin film using several matrixes derived from nafion, silica and other synthetic polymer. In this work, natade coco, a natural bacterial cellulose polymer, has been utilized as a matrix for preparation spin crossover triazoleiron(II) complexes. The morphology of the complex and the composition of elements on the surface of natade coco have been explored using SEM-EDX analysis.

This study focuses on the growth of Zinc Oxide (ZnO) nanostructures on SiO₂/Si(100) substrate via chemical bath deposition (CBD) with varying NH₄OH concentration and annealing temperature. The grown ZnOnanostructures were characterized via SEM-EDS for the surface morphology and elemental composition and UV-Vis spectroscopy for the reflectance measurement. Increasing the concentration of NH₄OH produced denser ZnOnanostructures composed of rods having smaller diameter. It is believed that at higher concentration of NH₄OH, more Zn(OH)₂ seed will act as nucleation site for ZnOformation which suggests higher probability of ZnOgrowth. Thermal annealing increased the average diameter of ZnOnanorods. Annealing provided enough energy for unstable atoms to rearrange into a more suitable position. This would result to larger rods that have been formed in expense of the smaller rods. Furthermore, it is confirmed in the UV-Vis spectroscopy results that ZnOnanostructures were successfully grown on SiO₂/Si(100) substrate. This successful growth of ZnOnanostructures is a promising material for solar cell technology.

The purpose of this project is to develop a local real-time river flood monitoring and warning system for the selected communities near MandulogRiver. This study focuses only on the detection and early warning alert system (via website and/or cell phone text messages) that alerts local subscribers of potential flood events. Furthermore, this system is interactive wherein all non-registered subscribers could inquire the actual water level of the desired area location they want to monitor. An estimated time a particular river waterway will overflow is also included in the analyses. The hardware used in the design is split into several parts namely: the water level detector, GSM module, and microcontroller development board.

Zinc oxide-silica (ZnO-SiO2) composite powders with different surface morphologies were synthesized via sol-gel process using rice husk ash as silica source. Micrograph results revealed the surface modification of bare ZnOfrom hexagonal tips to hemispherical tips after incorporation of SiO2 to ZnO. After annealing at 400 and 500°C, the hemispherical tips became more apparent due to the removal of the flaky particles associated to the complexes of zinc. Annealing the sample powders to 600°C sharp tips was observed on the morphology of ZnO-SiO2. Infrared spectroscopy further support that SiO2 was incorporated to ZnOdue to the Si-O-Zn band observed in the IR spectra. X-ray diffraction results verify the presence of amorphous SiO2 and the polycrystalline nature of the samples having particle size in nanometer scale. Furthermore, diffraction spectra show that thermal annealing removes the zinc complexes resulting to more pronounced hemispherical tips of ZnO-SiO2.

We have successfully synthesized zinc sulphide (ZnS) nanospheresdeposited on glass and silicon on insulator substrates as an acetic acid sensor. Results show that nanospheresdeposited on silicon on insulator substrate at lower ZnCl₂ concentration show better response and good recovery. We found out that the sensitivity of the ZnSnanosphereswere dependent on the surface morphology and that the morphology is affected by the ZnCl₂ concentrations and the substrates used. Our results show a promising potential of ZnSnanospheresas an inexpensive alternative sensing material to the existing acetic acid detectors.

Growing ZnO on Si via low-cost CBD is difficult owing to the large lattice mismatch between ZnO and Si and the intricate control of nanoparticle aggregation. In this work, a Pt buffer layer and addition of SiO2 on the chemical solution were introduced. The effect of these parameters on the resulting morphology and composition were investigated using SEM-EDX and FTIR. Pt-coated Si showed higher density of ZnO nanostructure growth than bare Si due to the additional nucleation sites provided by Pt. Moreover, SiO2 addition resulted to a different ZnO nanostructure.

In this report, the surface hydrophobicity of PDMS was investigated using two methods of preparations. The first method was performed by changing the surface roughness through the use of different molds. The second method was performed by varying the reconstitution ratio (volume of elastomer base to volume of elastomer curing) of the PDMS. Variation in the hydrophobicity of the PDMS was characterized by measuring the contact angle of a liquid droplet against the surface of the PDMS. The results showed that both the surface roughness and the reconstitution ratio of the PDMS positively correlated with the contact angle measured regardless of the liquid used. The maximum and minimum contact angle obtained were θ_r = (138 ± 3)° and θ_r = (99 ± 3)°, respectively. The results demonstrate a straightforward way of fabricating microfluidic devices using PDMS with controlled hydrophobicity.

Biological hydroxyapatite (BHAp) derived from thermally-treated fish bones was successfully produced. However, the obtained biological HAp was amorphous and thus making it unfavorable for medical application. Consequently, this research exploits and engineers the crystallinity of BHAp powders by addition of CaCO₃ and investigates its degree of crystallinity using XRD and IR spectroscopy. On XRD, the HAp powders with [Ca]/[P] ratios 1.42, 1.46, 1.61 and 1.93 have degree of crystallinity equal to 58.08, 72.13, 85.79, 75.85% and crystal size equal to 0.67, 0.74, 0.75, 0.72 nm, respectively. The degree of crystallinity and crystal size of the obtained calcium deficient biological HAp powders increase as their [Ca]/[P] ratio approaches the stoichiometric ratio by addition of CaCO₃ as source of Ca²⁺ ions. These results show the possibility of engineering the crystallinity and crystal size of biological HAp by addition of CaCO₃. Moreover, the splitting factor of PO₄ vibration matches the result with % crystallinity on XRD. Also, the area of phosphate-substitution site of PO₄ vibration shows linear relationship (R² = 0.994) with crystal size calculated from XRD. It is worth noting that the crystallinity of the biological HAp with [Ca]/[P] ratios 1.42 and 1.48 fall near the range 60-70% for highly resorbable HAp used in the medical application.

Growth of zinc sulphide (ZnS) nanostructures on silica modified-polyaniline (SM- PAni) with polymerization time-dependent was prepared using chemical bath deposition (CBD) technique. The grown samples were characterized by scanning electron microscopy (SEM) equipped with energy dispersive x-ray spectroscopy (EDS) and fourier transform infrared spectroscopy (FTIR). SEM images revealed that polyaniline rod-like nanostructures and ZnS nanospheres were successfully grown. The average diameter of the grown ZnS nanospheres did not significantly change by changing the growth time of the polyaniline. However, ZnS nanospheres grown with longer polymerization time of PAni is less dense and loosely bound as compared to shorter polymerization time of PAni. The less density of ZnS nanostructures with longer polymerization time of PAni may be due to the presence of PAni agglomerates that hinders the growth of ZnS nanospheres. Furthermore, FTIR spectra confirmed that the grown polyaniline is of emeraldine salt oxidation state which is the most conductive state of PAni.

Free standing, highly crystalline ZnO micro/nanorods have been successfully fabricated using low temperature hydrothermal synthesis. Current-voltage characteristic curves show that ZnO micro/nanorods' resistances are proportional to their geometrical ratios, satisfying classical Ohm's law. Temperature-dependent resistance measurements reveal exponential decay of current with temperature, implying good semiconducting properties. Finally, three different thermally-activated impurity levels were identified from the measurements, and these are attributed to Zn interstitials in the bulk. The results are important in supplementing research on nanoelectronics and nanocircuitries.

Different surface morphology of ZnO-SiO₂ has been successfully grown on glass and silicon substrates using chemical bath deposition method. The dependence on the substrates used on the morphology of ZnO-SiO₂ was investigated. The morphology of ZnO- SiO₂ on glass substrate was flake-like in form and changes to protruding hemispherical structures when grown on silicon substrate. Elemental composition analysis verified the presence of ZnO and SiO₂. Infrared characteristics showed an absorption band for the binding of ZnO and SiO₂ and revealed the presence of zinc complexes. We proposed a mechanism on the growth of ZnO-SiO₂ on glass and silicon substrate using low temperature deposition technique.

Different concentrations of Ru(bpy)²⁺₃ were successfully deposited on ITO coated glass substrates employing a simple method using a spin coater. The surface morphology was determined by scanning electron microscopy (SEM). The transport mechanism and the diffusion coefficient of the redox mediators within the films were characterized using cyclic voltammetry (CV). The concentrations were varied by dissolving different amounts of the redox mediator in methanol and 5% Nafion. SEM micrographs showed that the roughness of the surface increased with concentration of redox mediator. CV showed successful incorporation of Ru(bpy)²⁺₃. The order of the magnitude of the diffusion coefficients confirmed that the redox mediators were immobilized within the Nafion thin film. The resulting amount of redox mediator immobilized can be manipulated by simply varying the concentration of the casting solution.